Railway-traffic-controlling apparatus



I RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 30, 1929 TPain-- U V V V .A 1; I l a'cl zwqy B I L *\Q1zzmllad ]0-\, y Traffic Conditions.

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Patented Jan. 20, 1931 UNITED STATES PATENT OFFICE ms 0. GRONDAHL, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE nNIoN SWITCH & SIGNAL CO PA or SWISSVALE, PENNSYLVANIA, A CORPORATION OI PENNSYLVANIA I I RAILWAY-TRAFFIC-GON'IROLLING APPARATUS Application filed September 30, 1929. SerialNo. 396,188.

My invention relates to railway trafiic controlling apparatus of the type. comprising train carried governing means co-operating with devices located at intervals along {the i'trackway. l

I, will describe'one' form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

- The accompanying drawing is a diagrammatic view illustrating one form of railway trafiic controlling apparatus embodying my invention.

- Referring to the drawing, the reference character A designates a train carried rell ceiver comprising two 'magnetizable cores 1 and 3 located in inductive relation. The'core 1 is provided with a winding 2 which is con-. .stantly supplied with alternating current from a'suitable source, such as an alternator- G, and the core 3 is provided with a winding 4 in which an alternating electromotive force is induced by the-flux created by the current in winding 2 and linkingwinding 4.

Associated with the receiver A is a relaydevice, here shown as a grid glow-tube T.

The tube T consists of two spaced electrodes 5 and 6 and a grid 7 inclosed in a sealed envelope filled with a suitable medium such as neon gas. force, having a magnitude sufficiently great,

is applied across electrodes 5 and 6 of a tube}' of the type described, the medium surroundv ing the electrodes becomes conducting and a unidirectional current flows from electrode .5 l to electrode 6. The critical magnitude of the electromotive force necessary to cause tube'T to become conducting, however, is dependent upon the-potential and relative polarity of grid7 with respect to electrode 5, this critical magnitude decreasingas the potential of grid 7 increases when the grid is positive with respect to electrode 5, but increasing as the potential of grid 7 increases'when the grid is negativewith respect to electrode 5.

-A relay R is provided with a circuit includ ing its own front contact '12, alternator .G, and electrodes 5 and 6 of tube T. Winding l of receiver A is connected with electrode 5 and grid 7 of tube'T. The parts are so propor- 9.. tionedthat the electromotive. fo ce which is If an alternating electromotive.

induced in winding 4 under. normal conditions creates a difference of potential between grid 7 and electrode 5 which renders tube T conducting at the magnitude of the, electromotive forceimpressed across electrodes 5 and 6 by alternator G. Relay R is therefore normally energized over the stick circuit pie 1 viously described. I A i Relay may be used to control governing means on the train in any suitable manner. As here shown the relay'R controls a magnet valve M which is energized only when relay R is energized and which is arranged to apply the brakes on the train when the valve be comes de-energized. Located in the trackway' adjacent the path of "travel of the train carried receiver is a controlling element B comprising an inductor 8 .providedwith a winding 9. The winding 9llS providedwith a circuit controlled bya front contact 10 of a relay S. The relay S may be controlled in any suitable manner.-

traffic conditions in advance in such manner, that when traffic condltlons are safe, relay S is energizedto close contact 10, but that,

a For example, relay S may be controlled by is on open circuit. Under these conditions.

the inductor 8 shunts .fluxaway from the winding 4; so that the magnitude of the electromotive force induced in winding 4 is reduced. As a result, the difference of potentialbetween grid 7 and electrode 5 of tube T is changed to a value which renders tube T non-conducting, and relay R therefore becomes de-energized. When relay R becomes. de-energized, valve M becomes de-energized and. applies the brakes on the train; Inasmuch as the circuit for relay R includes a front contact 12 of this relay, the relay when once ale-energized, will remain tie-energized until the path through front contact 12 is shunted. This shunting may be accomplished for example by a manually operable push butten 1.? connected in mul ple with c n act 12.-

ing through the tube, and inthis way smooths out the pulsations in the direct current which is supplied to the relay when tube T is conducting. I

Although I have herein shown and described only one form of railway traific 'c'on-' trolling apparatus embodying my invention,

it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus comprising a train carried-tube having two spaced electrodes and a grid in a medium whioh forms 'a conducting path between said electrodes when and only when the potential between the electrodes eXce'e'ds a value which depends upon the relative potential of said grid with respect to one of said electrodes, a source of alternating current, a relay, means including said relay and a front contact of said relay for connecting said source across said electrodes, a winding on the train re ceiving energy from said source and connected between'said grid and said one elec trode for creating a difference oflpotential between said grid and said one electrode, means located in the tracliway for at times varying the energy received by said winding from said source, and governing means on the train controlled by said relay.

2. Railway traflic controlling apparatus comprisinga train carriedctube having two spaced electrodes and a grid in a medium which forms a cond' eting path between said electrodes when and only when the potential between the electrodes exceeds a value which winding on the train inductively coupled with said first winding and connected between said grid and said one electrode for creatinga difference of potential between said grid and said one electrode, means lowhich forms a conducting path between said electrodes when aindionly when the potential between the electrodes exoeedsa value which depends upon the relative potential'of said grid witl respect toone of said electrodes, a source'of alternating current, a relay, means including said relay and a front contact of said relay for connecting said source across said electrodes, a first train carried core provided with a first winding which is con stantly supplied with current from said sonrce, asec'ond train cai'ri'edcore' in indt1c= tive relation with said first core and provided with a second winding in which an electromotive force is induced by the flux created by the current in said first winding, means for connecting said second winding between said grid and said one electrode, means-lo;

cated in the trackway for at times shunting flux away from said second core to reduce the electromotive force indiiced in said second windlng; and governmg means on the train controlled by said relay. l

4. Railway traflic controlling apparatus comprising a train carried tube-having two stantly supplied with current from said 7 source, a second train carried core in inductiv'e relationtosaid first core provided with a second winding in which an electroinotive force is induced by the finx created by the current 1n said first winding, means for con-x necting said second winding between said grid and said one electrode for normally creating a difference of potential between said grid and said one electrode which renders said tube conducting, a trackway inductor located adjacent the path of travel of said train carried cores in such manner that when said train carried cores are over said trackway inductor, the electromoti've force induced in said second winding is at timesre duced to a value which renders said tube nonconducting, a winding on'said inductor pro-' vided with a circuit controlled by trafii'c conditions, and governing means on the train controlled by said relay.-

5; Railway traflic contnolling apparatus comprising a train carried receiver having two windings in inductive relatlon, a source of alternating current connected with one said winding, a grid glow tube having two electrodes and a grid in a medium which forms a conducting path between said electrodes when and only-when the potential between the electrodes exceeds a value which depends upon the potential of said grid with respect to one of said electrodes, means for connecting the other said winding between said grid and said one electrode, a train controlling circuit including a source of current and the electrodes of said tube, and trackway means for at times varying the flux from said one winding which links said other winding.

In testimony whereof I affix my signature.

LABS O. GRONDAHL. 

